Flashcards in Abx II (lecture) Deck (49):
What is the MoA of linezolid?
Bind to 50s of bacterial tRNA, preventing 70s formation
What is the spectrum of Linezolid?
Broad G + specific
What is the indication of Linezolid use?
Multi drug resistant strains
What is the mechanism of linezolid resistance?
Mutation of the 50s subunit preventing linezolid binding
What consideration is related to linezolid use with andrenergics, serotonergics and high tyramine intake (wine, cheese, and picked meats)?
Enhanced effects may result
What are two drugs are considered tetracyclines (other than tetracycline of course)?
Doxycycline and Minocycline
What is the mechanism of tetracyclines?
Bind the 30s subunit
What is the spectrum of tetracyclines?
Broad, mostly G +
What Rx is indicated in Lyme disease?
How does milk influence tetracycline uptake?
What are two absolute contraindications of tetracycline use?
Pregnancy and under 8 y.o.
What are the three mechanisms of tetracycline resistance?
Tet-O: Ribosome protecting proteins
What is the MoA of tigecycline?
Bind the 30s subunit
What is the spectrum of tigecycline?
Broad G + and G - anaerobe and aerobes
What "-cycline" is safe for use in renal failure and mild hepatic failure?
What is the MoA of tigecycline (2) resistance?
Streptomycin, gentamicin, neomycin, kanamycin and spectinomycin are all examples of what class of Abx?
What is the MoA of aminoglycosides?
Bind 30s subunit and initiate premature termination
What is the spectrum of aminoglycosides?
Broad G - aerobics
What are the 4 main adverse effects of aminoglycosides?
Curare-like muscular blockade
With which Abx group are aminoglycosides synergistic?
What are the 2 mechanisms of amino glycoside resistance?
Decreased permeability to inner membrane
What is the MoA of chloramphenicol?
Prevent transferase on the 50s subunit
What is the spectrum of chloramphenicol?
Broad G -, most anaerobes
How is chloramphenicol metabolized?
Hepatic inactivation and renal excretion
What are the clinical uses of chloramphenicol?
Limited: typhoid, bacterial meningitis, anaerobe infections, rickettsial
What is the MoA of chloramphenicol toxicity?
Mitochondrial 70s ribosome inhibition
What is the concern with administration of chloramphenicol to neonates?
Gray baby syndrome (40% fatal)
What is the mechanism of resistance with chloramphenicol and in what bacteria (2 genera) is this a primary concern?
Decrease membrane permeability
Salmonella and Shigella
What drug classification do erythromycin, clarithromycin, and azithromycin fall under?
What is the spectrum of macrolides?
G + >> G -
What is the DoC of sinusitis and mild pneumonia?
How are microlides excreted?
What macrolide is contraindicated in pregnancy, which is used?
Erythromycin is contraindicated
Azithromycin is used
What are the mechanisms (4) of resistance to macrolides?
MLSB decreased binding
Decreased RNA binding
What drug is indicated for B. fragilis, Peptococcus, and Clostridium?
What are the routes of clindamycin administration?
All: oral, topical, IM or IV (fro serious infections)
What are the 3 sites of clindamycin adverse effects?
neuromuscular transmission inhibition
- Life threatening pseudomembranous enterocolitis
- C. difficile overgrowth
Skin: Rash (esp with HIV and AIDS pts.)
What is the benefit of clinamycin over macrolides?
No ATP dependent efflux
What class of Abx ends in "-pristin"?
What is the DoC for vancomycin-resistant F. faecium and S. aureus and Strep pyogenes skin infections?
How are quinupristin and dalfopristin synergistic?
dalf enhances quin binding, which inhibits translocation
What is a special consideration of streptogramin administration?
5% dextrose only over 1 hr
How do streptogramins effect liver metabolism?
What are the 3 mechanisms of streptogramin resistance?
MLSB mutations fo rRNA
Lactonase and acetyl transferase
What is the first line drug for UTI?
What may nitrofurantoin induce in G6PD?
What is a special consideration of nitrofurantoin used during pregnancy?
Safe during first 6 months